Earth, Moon, and Sun
by: Nick Thomas
Where I did Moon Tracking-KMS
Section 1-Earth in Space
How does Earth move in space?
Earth moves by rotation and revolution in space.
An axis is an imaginary line that passes through Earth's center and the north and south poles. Rotation is the spinning of Earth on its axis. Earth's rotation causes day and night; the side of Earth facing the sun has day, while the side facing away has night. Since one rotation takes 24 hours, that's how long one day is.
Earth also travels around the sun. Revolution is the movement of one object around another. A complete revolution of Earth around the sun is a year. An orbit is a path Earth follows as it revolves around the sun. Earth's orbit isn't exactly circular. It is a slightly elongated circle or an ellipse.
What causes the cycle of seasons on Earth?
There are four seasons regions outside the tropic have:winter, spring, summer, and autumn of fall. Earth's axis has a tilt of 23.5°. Depending on where the Earth is in its rotation around the sun, the part of Earth facing the sun changes. The hemisphere of Earth facing the sun gets more direct sunlight, causing the seasons.
Section 2-Gravity and Motion
What determines the strength of the force of gravity between two objects?
The force of gravity depends on the the mass of the objects and the distance between the objects.
Gravity attracts all objects towards each other. Newton's law of universal gravitation states that every object in the universe attracts every other object. Gravity is measured in newtons, after Isaac Newton.
Gravity depends on mass of objects, which is the amount of matter in an object. You don't feel the force of gravity on something like a book because it isn't big enough. Weight is the force of gravity on an object. The weight of an object can change depending on its location, for example you would weigh a lot less on the moon then on Earth. Gravity also depends on the distance between objects. The farther away you get from an object, the gravity decreases; and the closer you get, the gravity increases.
What two factors combine to keep the moon and Earth in orbit?
Inertia and gravity combine the keep the Earth and moon in orbit.
Inertia is the tendency of an object to resist a change in motion. If you are in a car and it suddenly stops you keep moving forward, which is inertia. Newton's first law of motion says tat an object at rest will stay at rest and an object in motion will stay in motion with a constant speed and direction unless acted on by a force.
Since Earth is moving around the sun and, its inertia keeps it moving. The suns gravity pulling on the Earth stops it from going straight out into space.
Section 3-Phases, Eclipses, and Tides
What causes the phases of the moon?
The different shapes of the moon seen from earth are called phases. The moon goes through a full cycle of phases each time it travels around Earth.
Phases are caused by the change in the relative position of the moon, Earth, and sun. The sun lights up the moon, but sometimes Earth is blocking the light from the sun to the moon, causing a shadow on the moon. the cycle lasts for about 29.5 days.
What are solar and lunar eclipses?
An eclipse is when an object in space comes between the sun and another object causing a shadow on the third object.
A solar eclipse occurs when the moon passes directly between Earth and the sun, which then blocks sunlight from earth. An umbra is the darkest part of the moon's shadow, which is cone shaped. From the umbra, light from the sun is completely blocked, causing a total eclipse on the parts of earth that the umbra hits. The air becomes cooler, it becomes dark outside, the sky becomes an eerie color, and you can see the solar corona; which is the little bit of light around the sun. The large part of the moon's shadow is called the penumbra. Part of the sun is still visible from earth, so it isn't safe for your eyes to look directly at the sun.
A lunar eclipse occurs at a full moon when earth blocks sunlight from reaching the moon. The moon then looks dimmer since its in Earth's shadow. The Earth's shadow has a umbra and penumbra too. A total lunar eclipse can be seen anywhere on Earth that that the moon is visible, so you are more likely to see a lunar eclipse than a solar eclipse. Most of the lunar eclipses the Earth, moon, and sun aren't exactly aligned so a partial eclipse occurs.The moon passes partly into the umbra of Earth's shadow. The edge of the umbra appears blurry.
What causes the tides?
Tides are the rise and fall of ocean water about every 12.5 hours. Tides are caused mainly by the differences in how much the moon's gravity pulls on the earth. Where the moon is closer the gravity is stronger, so there is high tide. The farther the moon is from a certain space the gravity is less, causing low tide. The sun's gravity also pulls on the Earth's water. During a new moon the sun, Earth, and moon are almost in line, so the moon and sun both pull on the water. This causes the largest distance between high and low tide, or a spring tide. During the first and third quarter the moon and sun are at a right angle from each other, so they don't pull on the Earth as much as during a new moon. This causes the shortest distance between a high and low tide, or a neap tide.
Section 4-Earth's Moon
What features are found on the moon's surface?
Features on the moon's surface include maria, craters, and highlands.
The dark surfaces on the moon are maria, which means sea in Latin. Galileo thought that these were seas, but they are really hardened rock formed by lava from 3-4 billion years ago.
The round pits on the moon are called craters. Some craters are hundreds of kilometers across. Scientists thought that these were made from volcanoes, but they are from meteoroids; or chunks of rock and dust from space. There are few craters on or around the maria, which means that the craters were caused early in the moon's history. The craters on Earth have been worn away from erosion; but since the moon has no water of atmosphere, its surface hasn't changed for billions of years.
Galileo correctly inferred that that the light colored features on the moon's surface are highlands or mountains. The lunar highlands cover much of earth's surface.
What are some characteristics of the moon?
The moon is Earth's closest neighbor in space. The moon, though, is very different from the Earth. The moon is dry and airless. Compared to Earth, the moon us small and has large variations in its surface temperature. The moon is 3,476 kilometers in diameter, a little less than the distance across the US. The moon's density is similar to Earth's outer layers. The temperature on the moon varies from 130℃ to -180℃. The temperature varies so much since it has no atmosphere.The moon has no liquid water, but there might have been large patches of ice near the moon's poles. Some places are blocked from sunlight by craters, where water would remain frozen. if a colony was to built on the moon, there would be no water and it would be expensive to transport the water to the moon.
How did the moon form?
There are many theories as to how the moon formed, but many have flaws in them that prove them wrong. There is one theory, though, that seems the most logical; called the collision ring theory. Around 4.5 billion years, there were many rocky debris in the solar system. The theory states that a planet- sized object collided with Earth and formed the moon. The objects that exploded then went into orbit around Earth and gravity caused them to combine to form the moon.